The field of the invention is camera dollies. More specifically, the application relates to a system for allowing quick change of wheels on a camera dolly.
In motion picture or video filming, cameras are often supported on camera dollies, so that camera lens positions, angles, and elevations may be smoothly and easily achieved without interruption. Most camera dollies are pushed by xe2x80x9cdolly gripsxe2x80x9d or camera dolly operators. For use on a relatively smooth and hard surface, such as on a sound stage, or other indoor set, the camera dolly is preferably provided with solid tires having relative high hardness, to reduce rolling friction, and make it easier to push and maneuver the camera dolly. For use on more irregular, surfaces, for example an indoor surface having small cracks, bumps, etc., a softer solid tire is preferred, to absorb shock impulses, albeit with a small increase in rolling friction. For use on still more irregular surfaces, pneumatic tires are typically used, to provide a higher degree of shock absorption, although with a slightly greater increase in rolling friction. For use on unpaved surfaces, such as grass, sand, etc., or in other applications where a maximum level of smoothness in dolly movement is required, dolly track is laid down, with the dolly wheels rolling on the smooth metal rails of the track. Having a smooth rolling surface, or a way to absorb the shock impacts created when rolling over an irregular surface, is important, as shock impacts generated via the rolling movement of the camera dolly wheels can cause unacceptable movement of the camera lens during filming, resulting in unsteady recorded images.
It is frequently necessary to change the wheels on the camera dolly, to compensate for change in the ground conditions. For example, if a first part of a film sequence takes place indoors, the hard solid wheels may be used. Then, if the sequence continues outdoors, it may then be necessary to change over to a pneumatic or track wheel. While a combined track/pneumatic wheel, as described in U.S. Pat. No. 4,943,101, incorporated herein by reference, has been successfully used in the past, to avoid to wheel changeover when switching between track and pneumatic wheels, it remains necessary to change wheels when the harder solid wheels are needed.
Wheel changeover has conventionally required time and tools. Typically, a screwdriver or wrench is needed to remove a fastener from an axle to remove, and then reinstall, a wheel. As most camera dollies have one pair of wheels at each corner, for a total of eight wheels, wheel changeover can be time consuming. Typically, changing over each wheel, even for a skilled camera dolly grip, requires e.g., 60-80 seconds, so that changing over eight wheels typically takes about 10 minutes. While in most endeavors, ten minutes may be acceptable, motion picture production often requires a large number of highly skilled professionals, and extensive amounts of equipment and supplies, so that production costs can reach $1,000 per minute. Accordingly, saving even a few minutes in production time is highly significant, in terms of production costs. Moreover, in sequences involving fast changing lighting conditions, the ability to film the sequence as desired may depend on how quickly the equipment, including the camera dolly, can be set up.
Accordingly, there remains a need for designs which allow fast changeover of camera dolly wheels.
In a first aspect of the invention, a camera dolly has a plurality of axles connected directly or indirectly to a camera dolly chassis. The camera dolly wheels are secured onto the axles by quick release clip assemblies. The clip assemblies can be quickly and easily removed and reinstalled, by hand and without tools, to allow fast wheel changeover.
Preferably, a cap is attached to each of the axles, and the quick release clip has a spring which engages the cap. The clip is released by pulling the spring away from the cap, and sliding the clip off of the axle.
In a second aspect of the invention, the release clip has a U-shaped frame having bosses extending outwardly from a land area. The cap preferably has a shaft, a shoulder, and a top surface. The U-shaped frame is advantageously engageable around the cap, with the shoulder of the cap against the land area of the U-shaped frame.
In a third aspect of the invention, the axles of the camera dolly have a diameter equal to or greater than the diameter of the cap, so that the wheels can be removed from the axles, after the quick release clip is removed, but without removing, the cap.
In a fourth aspect of the invention, in a method for wheel changeover in a camera dolly, a second wheel of the camera dolly is rolled up onto a wedge, so that a first wheel of the camera dolly is lifted off of the ground. A quick release clip holding the first wheel onto the first axle is released and removed. The first wheel is removed and replaced with another wheel, and the clip reinstalled. Use of the ramp avoids the need to lift the wheels off the floor to achieve wheel changeover.
Accordingly, it is an object of the invention to provide a fast wheel changeover system for a camera dolly. Other and further objects and advantages will appear below.